1. Field of the Invention
This invention relates to a catalytic method for the preparation of diazabicyclo-(2.2.2.)-octane (triethylenediamine). More particularly, this invention relates to a catalytic method for the manufacture of triethylenediamine from N-hydroxyethyl piperazine. Still more particularly, this invention is directed to the use of titania-supported tungstopyrophosphate catalysts to catalyze the cyclization of N-hydroxyethyl piperazine to form triethylenediamine. Even more particularly, the present invention is directed a continuous process for the manufacture of triethylenediamine from N-hydroxyethyl piperazine by passing such feedstock over a bed of catalyst in a reaction zone wherein the catalyst is composed of pellets of a titania-supported tungstopyrophosphate catalyst.
2. Prior Art
Vanderpool et al. U.S. Pat. No. 4,806,517 discloses the preparation of linear polyethylene polyamines by reacting ethylenediamine with monoethanolamine in the presence of a group IVB transition metal oxide to which from about 0.5 to 7 wt. % of phosphorus has been thermally chemically bonded.
Knifton et al. U.S. Pat. No. 4,683,335 discloses the use of tungstophosphoric acid or molybdophosphoric acid-ontitania catalyst for this purpose.
It has heretofore been proposed to manufacture triethylenediamine from a wide variety of cyclic and acyclic polyethylenepolyamines. For example, Brader U.S. Pat. No. 3,157,657 discloses the preparation of triethylenediamine from N-aminoethyl piperazine using a catalyst comprising tungsten or a base modified silica alumina cracking catalyst (see also, Brader U.S. Pat. No. 3,120,526). U.S. Pat. No. 3,080,371 discloses the use of an organic carboxylic acid to catalyze the conversion of hydroxyethyl piperazine to triethylenediamine.
Brader et al. U.S. Pat. No. 3,297,701 discloses a method for the preparation of triethylenediamine by bringing an appropriate feedstock such as a cyclic or acyclic polyethylenepolyamine (e.g., N-aminoethyl piperazine, monoethanolamine, etc.) into contact with a phosphate of an enumerated metal (e.g., aluminum, calcium or iron phosphate). Also, Brader et al. propose the use of 2-(2-hydroxyethoxy) ethylamine as a feedstock for the synthesis of triethylenediamine in U.S. Pat. No. 3,172,891 using an aluminum phosphate catalyst.
Muhlbauer et al. U.S. Pat. No. 3,285,920 is directed to a continuous process for the manufacture of piperazine and triethylenediamine wherein N-aminoethyl piperazine is converted to triethylenediamine using a silica-alumina cracking catalyst alone or modified with alkaline earth metal oxides, alkali metal oxides, zirconia, etc., a tungsten catalyst or a phosphate salt such as a phosphate salt of aluminum or iron.
Vanderpool et al. U.S. Pat. No. 4,757,143 discloses the use of a zirconia on titania support having 0.5 to 7 wt. % of phosphorus bonded thereto for converting a wide variety of cyclic and acyclic hydroxyethyl ethylene polyamines to triethylenediamine.
Vanderpool et al. U.S. Pat. No. 4,754,036 discloses the use of the same class of catalysts for the conjoint manufacture of N-allyl piperazine and 2-methyl triethylenediamine from N-hydroxypropyl piperazine.